In a wireless communication system based on an Orthogonal Frequency Division Multiplexing (OFDM) technology, generally speaking, in one basic time domain time period (such as one subframe), some basic channels and signals such as a control channel, a data channel, demodulation reference signals for the control and data channels need to exist. In some cases, a channel measurement reference signal, a positioning reference signal and a synchronization signal also need to exist. Here, the basic time domain time period has different definitions and names in different systems.
Generally speaking, channels in a resource block (RB) are multiplexed in a time-frequency division multiplexing manner. For example, a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Shared Channel (PDSCH) are time division multiplexed; an Enhanced Physical Downlink Control Channel (EPDCCH) and the PDSCH are frequency division multiplexed; a Physical Hybrid ARQ Indicator Channel (PHICH) and the PDCCH are a mixed time-frequency division multiplexed; and signals and channels are also mixed time-frequency division multiplexed. For example, a Cell specific Reference Signal (CRS), a Demodulation Reference Signal (DMRS, also called UE specific RS), and a Channel State Information-Reference Signal (CSI-RS) are all embedded into the PDSCH. In a Long Term Evolution (LTE) system, main signals and channels in one RB are shown in FIG. 1.
The design of the current 4G wireless communication system has several typical features.
All channels and signals are not well distinguished in the time domain, and the time domain coupling is very strong. Time-frequency transmission resources of multiple channels or signals are included in one symbol. For example, the OFDM symbol in which the PDCCH is located includes the CRS corresponding to the control channel; the OFDM symbol in which the data channel is located includes the CRS and the DMRS, and probably the CSI-RS and the positioning reference signal (PRS). In addition, the PHICH or Physical Control Format Indicator Channel (PCFICH) may also be mixed into a PDCCH symbol, the EPDCCH may also exist in the PDCCH symbol (multiplexed in different RBs). All channels and signals in one frame all use a same basic transmission parameter set, such as subcarrier spacing, Cyclic Prefix (CP) of the OFDM symbol, the subcarrier number in per unit of bandwidth, Fast Fourier Transformation (FFT) points and baseband modulation waveform.
At least the following drawbacks exist in the related art. Different channels or signals actually have different features. For example, the control channel requires higher robustness, and the reference signal is more important to channel measurement and data demodulation. Therefore, different channels actually may have different basic transmission parameters. However, the current transmission parameters of the system are not flexible. In addition, in a case of radio frequency precoding, since the same radio frequency beam acts on this frequency band, when the bandwidth is larger and the number of subcarriers is bigger, the resource waste exists.